Nortel Networks NN46110-602 manual Chapter Packet capture

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Chapter 5

Packet capture

Packet capture (PCAP) is a troubleshooting tool that network administrators and customer support personnel use, in conjunction with other tools such as statistics, logging, network analyzers, and testers, to remotely troubleshoot VPN Router and network problems. Packet capture is especially useful for troubleshooting the VPN Router 1010/1050/1100, which is typically located in a small office where no technical expertise is available. You can only configure PCAP with the command line interface (CLI).

There are two options when capturing packets:

•No packet loss—captures all packets. If the RAM buffer is full, a forced flush to disk occurs.

•Packet loss—skips some packets. If the RAM buffer is full, the VPN Router drops packets and inserts a malformed packet in the place where the packets were not captured. The malformed packet stores the number of dropped packets.

Note: While capturing packets with packet loss does not affect forwarding performance, capturing packets with no packet loss can affect performance.

When capturing packets traversing the VPN Router, you can do one of the following:

•write them to files in a circular buffer of maximum 999 files

•write them to stop when the specified maximum number of files is reached

Nortel VPN Router Troubleshooting